There exist various traditions in extrabiblical sources claiming that Noah had children other than Shem, Ham, and Japheth, born variously before, during, or after the Deluge.

According to the Quran (Hud v. 42-43), Noah had another unnamed son who refused to come aboard the Ark, instead preferring to climb a mountain, where he drowned. Some later Islamic commentators give his name as either Yam or Kan'an.

According to Irish mythology, Noah had another son named Bith, who was not allowed aboard the Ark, and who attempted to colonise Ireland with 54 persons, only to be wiped out in the Deluge.

Some 9th century manuscripts of the Anglo-Saxon Chronicles assert that Sceafa was the fourth son of Noah, born aboard the Ark, from whom the House of Wessex traced their ancestry; in William of Malmesbury's version of this genealogy (c. 1120), Sceaf is instead made a descendant of Strephius, the fourth son born aboard the Ark. An early Arabic work known as Kitab al-Magall or the Book of Rolls (part of Clementine literature) mentions Bouniter, the fourth son of Noah, born after the flood, who allegedly invented astronomy and instructed Nimrod. Variants of this story with often similar names for Noah's fourth son are also found in the ca. 5th century Ge'ez work Conflict of Adam and Eve with Satan (Barvin), the ca. 6th century Syriac book Cave of Treasures (Yonton), the 7th century Apocalypse of Pseudo-Methodius (Ionitus), the Syriac Book of the Bee 1221 (Yônatôn), the Hebrew Chronicles of Jerahmeel, ca. 12th-14th cent. (Jonithes), and throughout Armenian apocryphal literature, where he is usually referred to as Maniton; as well as in works by Petrus Comestor c. 1160 (Jonithus), Godfrey of Viterbo 1185 (Ihonitus), Michael the Syrian 1196 (Maniton), Abu Salih the Armenian c. 1208 (Abu Naiţur); Jacob van Maerlant c. 1270 (Jonitus), Abraham Zacuto 1504 (Yoniko) and Jehiel ben Solomon Heilprin c. 1697 (Yuniku).

Martin of Opava (c. 1250), later versions of the Mirabilia Urbis Romae, and the Chronicon Bohemorum of Giovanni di Marignola (1355) make Janus (i.e., the Roman deity) the fourth son of Noah, who moved to Italy, invented astrology, and instructed Nimrod.

According to the monk Annio da Viterbo (1498), the Hellenistic Babylonian writer Berossus had mentioned 30 children born to Noah after the Deluge, including sons named Tuiscon, Prometheus, Iapetus, Macrus, "16 titans", Cranus, Granaus, Oceanus, and Tipheus. Also mentioned are daughters of Noah named Araxa "the Great", Regina, Pandora, Crana, and Thetis. However, Annio's manuscript is widely regarded today as having been a forgery.

According to Jewish tradition the inhabitants of the Ark, including the humans were not allowed to mate, therefore Noah could not have had any children while on the Ark. Directly after coming out of the Ark, Noah got drunk and according to Jewish tradition was castrated by his son Ham, preventing him from having any more offspring.